This is actually part of our (Australia's) Australian consumer protection laws, which are considered pretty beastly.

Its simply a test of reasonableness. If you had another source of information about a likely fault and you purchased anyway, it can reduce your protection.

If you have a reasonable expectation that a brand is really good and often lasts 7 plus years it can also go the other way. Netting you government guaranteed replacements by manufacturers far longer than their competitors.

I wasn't applying any free market assumptions here, but the (very popular) regulatory framework I already live under.